a. Field of the Invention
This invention relates to circuit protection devices and related control systems.
b. Related Art
A step-type voltage regulator is a circuit protection device which is used to maintain a relatively constant voltage level in a power distribution system. Without such a regulator, the voltage level of the power distribution system could fluxuate significantly and cause damage to electrically powered equipment.
A typical configuration for this type of regulator (such as the Siemens JFR Series) is shown in FIG. 1. The conventional step-type voltage regulator 102 of FIG. 1 includes a microprocessor based controller 104 which generates signals that cause regulator tap changes in accordance with user configured thresholds and setpoints. The windings and other internal components that form the transformer are mounted in an oil filled tank 106. A tap changing mechanism (not shown) is sealed in a separate chamber in lower portion of the tank 106. The various electrical signals generated by the transformer are brought out to a terminal block 108 and external bushings S, SL, L for access. An indicator 110 is provided so that the position of the tap as well as its minimum and maximum positions can be readily determined.
A cabinet 112 is secured to the tank to mount and protect the voltage regulator controller 104. The cabinet 112 includes a door (not shown) and is sealed in a manner sufficient to protect the voltage regulator controller 104 from the elements. Signals carried between the transformer or tap changing mechanism and the voltage regulator controller 104 are carried via an external conduit 114.
From time to time, a manufacturer will make enhancements to the controller 104. These enhancements are typically provided by way of replacement of one or more of the controllers internal parts, modification of the controller's resident program code or by replacement of the controller itself. Upgrading or enhancing the functionality of a controller in this manner can be expensive and time consuming. Further, a user may wish to pick and choose from a number of enhancements.